Electromechanical time relay

ABSTRACT

An electromechanical time delay device driven by a synchronous motor via a reduction gear system, in which a series of decadic time ranges can be preselected. A time delay required is selected with the chosen decadic range by means of an adjustor Knob associated with a time scale. Within each decadic range, the lower end of the scale can be expanded by the use of further reduction gears so that the effect of the inherent time error of the relay is minimized.

United States Patent n91 Hauie (451 Jan. 30,1973

541 ELECTROMECHANICAL TIME RELAY [75] Inventor: Werner Haute, Berlin, Germany [73] Assignee: Sehleicher G.m.b.H. 8: Co.

Relaisbau K.G., Berlin, Germany [22] Filed: Oct. 27, 1970 [21] Appl. No.: 84,268

[52] U.S. Cl. ..58/39.5, 200/38 R [51] Int. Cl ..G04f 3/06 [58] Field ofSearch.....58/16,19, 21.13, 21.14, 39.5,

[56] References Cited UNITED STATES PATENTS 2,786,525 3 1957 Vigneauxnl ..5s 127 R 2.864.443 12/1953 Niemand Use/sons 3,568.42) l/l969 DeLille .ss/ms Primary Examiner-Richard B. Wilkinson Assistant Examiner-Edith C. Simmons Jackman AltorneyPau1 M. Denk [57] ABSTRACT An electromechanical time delay device driven by a synchronous motor via a reduction gear system, in which a series of decadic time ranges can be preselected. A time delay required is selected with the chosen decadic range by means of an adjustor Knob associated with a time scale. Within each decadic range, the lower end of the scale can be expanded by the use of further reduction gears so that the effect of the inherent time error of the relay is minimized.

5 Claims, 2 Drawing Figures PMENIEuJmo'wn 3.713.285

SHEET 1 [IF 2 Fig.1

Inventor: I

WERNER war:

ELECTROMECHANICAL TIME RELAY The invention relates to an electromechanical time delay device with a synchronous motor reduction gear ing, wherein the time sequence, which is continuously preselectable over an indicating scale by means of an adjusting knob on the faceplate, can be spread over a number of decadic stages by means of a second selector knob. This device can be utilized to provide for a delay in the operation of, for example, a relay, solenoid, and the like.

Time delay relays in which the adjustable time-elapse wheel can be driven by means of a synchronous motor via reduction gearing, are generally known. The use of a synchronous motor as the time-elapse element for the relay is particularly advantageous, since it is known that motors of this type run at a very constant speed of rotation and are relatively insensitive to fluctuations in the mains voltage. However, synchronous motors have a relatively high running speed, with the result that the rotational speed of the pinion on the output side 'has to be reduced in a suitable manner by way of one or more reduction gear systems.

The known reduction gear systems used in time delay relays are generally designed in such a way that the individual gear wheels are disposed with their shafts on a circular line, the said shafts being located concentrically around the centrally-mounted adjusting shaft. in the case of time relays which are provided with a selector knob for the range preselection of different time intervals, the adjusting shaft carries, at the opposite end from the adjusting knob, a double gear wheel arrangement with which it is possible to selectively interpose more or fewer gears of the reduction gearing, before the time-elapse wheel. Because of this, the continuously preselectable time lapse, which can be set for individual operations in accordance with the desired time delay, can be spread discontinuously in a number of stages, this spreading preferably occurring decadically in known time delay relays.

The known time delay relays with a synchronous motor may be of either continuous-running or simultaneous-starting design, that is to say the synchronous motor may, when a voltage is applied, also run continuously outside thepreselected time lapse, as a result of which a flying start for the remaining lines of the time delay relay is produced at the start of a time-elapse period, or else the synchronous motor may be controlled in such a way that it starts to run at the same time as the time lapse which has been set commences. In any case, the output gear of the reduction gearing has to be coupled to the time-elapse gear afterexcitation of, for example, an electromagnet which triggers the switching operation inside the time relay, as known in the art.

This coupling-in operation brings about an undesireable time error in the relay. This time error is caused by the fact that, during the coupling operation, the aforesaid output pinion or gear of the reduction gearing does not always engage fully and immediately with its teeth in the teeth of the time-elapse gear, but instead, the teeth of the two gears sometimes strike againsteach other, and only after this engage with one another in a non-slip manner. This error, which is brought about by the coupling operation, gives rise to inaccuracy in the adjustment of the overall time lapse and appears again with each switching operation. Furthermore, the error is independent of the particular time set, with the result that, relatively speaking, it is particularly large, and therefore of considerable consequence, when the time lapses set are only short.

Attempts have been made to keep this coupling error small by providing a particularly large number of teeth, of the smallest possible size, on the time-elapse wheel. Generally speaking, however, the limitations of this measure lie, on the one hand, in the possible tooth modulus and also in the size of the time delay relay. Since the dimensions of time relays should naturally be kept relatively small, the time-elapse wheel cannot be selected beforehand at any desired size, but must likewise have the smallest possible diameter. The reduction gearing, per se, must also be designed to save as much space as possible and must be disposed inside the time relay.

For the adjustable time ranges, the manufacturers of known time delay relays indicate an absolute error for the adjustment which is, on average, 10.5 percent, measured over a complete scale range. In the case of time adjustment values which are smaller than a complete scale deflection, and particularly in the case of one which lie in the lower range of the scale, .the coupling error, which remains constant, is of considerably greater consequence, regarded from an absolute point of view, than in the case of time ranges which, after preselection, extend over approximately the whole range of the scale. Thus, for example, a time error which is indicated as i 0.5 percent over the full value of the scale, amounts to t 5 percent in the case of a time setting of 1 10 of the total scale deflection, or even i 10 percent in the case of 1/20 of the total amount of-the scale. Thus, the time error does not appear in the setting in a linear manner, in dependence upon the individual scale values, but instead occurs exponentially, while the inaccuracy of timing increases particularly strongly in the case of short-term settings.

In this connection, a time delay relay has already become known which permits setting over two different scale ranges. In this relay, there is provided on the faceplate of the time relay, near the setting knob which permits continuous preselection of time over a given range, a second preselector knob which makes it possible to switch the time relay over from one time range to the other. Accordingly, the faceplate of the time-relay is also provided with two scales which correspond to the two time ranges to be set. in this case, the time ranges overlap in such a way that an individual, given time range can be partially expanded, in its lower range, by switching over the preselector knob.

A disadvantage of this known time delay relay, however, resides in the fact that it only operates with a single time range, which can be only partially expanded in its lower range, while the advantages which can be obtained with other known time relays, which provide a number of decadic stage systems for the time ranges, are not applied. 1

in modern switching technology, increased requirements are imposed upon time delay relays, there being a demand for very different time ranges and therefore time preselection control operations of widely differing lengths, which have to be put into effect with one and the same relay, solenoid, or other device to be operated.

The underlying aim of the invention, therefore, is to reduce the error produced in the coupling-in operation of the time lapse in electromechanical time delay devices, such as relays, with a synchronous motor and reduction gearing, in which the time sequence, which is continuously preselectable over an indicating scale by means of an adjusting knob on the faceplate, can be spread over a number of decadic stages by means of a second selector knob, and in this event to permit a reduction of the error to above one-third, particularly in the lower time range.

In accordance with the invention, there is provided an electromechanical time relay comprising a synchronous motor for selectively driving via a reduction gear system, a time elapse wheel, electromagnetic switch means (not shown) of the type normally associated with the time elapse wheel and operable to effect switching of a relay in accordance with the setting of an adjuster knob associated with a time elapse indicating scale, the time delay of the relay being continuously preselectable by said knob within one of a plurality of decadic ranges selectable by a second knob, the decadic ranges each corresponding to a specific reduction ratio within the reduction gear system and being directly associated with further reduction gears for effecting expansion of the lower ranges within each decadic time range.

In this connection, it is particularly advantageous if the expansion of the lower range is identical within each decadic time stage, while the indicating scale for the continuous preselection of the time sequence is associated with only a single indicating scale which corresponds to constant spreading.

It is also preferable that the indicating scales on the selector knob, which in known manner are of multicolored design, are associated with those colors within appertaining segments, which correspond to the individual time ranges.

In a preferred example of embodiment, the invention is finally characterized by the fact that there are provided three decadic time ranges of one second, 10 seconds and I seconds, which are associated with time ranges of3 and 30 seconds.

Through the fact that the decadic time stages are associated, within the reduction gearing, with further reduction gears, it is possible to effect advantageous expansion of, in particular, the lower range of a time scale, that is to say, it is possible for the time-elapse wheel, which, when small time ranges are set, returns over only a relatively small angle of rotation, to return over the complete angle of rotation, or at least over a relatively large angle of rotation, when the same time is set. In this way, the error, inherently constant, which occurs as a result of the coupling of the output pinion of the gearing to the time-elapse wheel and which is of considerable consequence, particularly for small time ranges, can be reduced (relatively speaking). Thus, for example, in the case of a time scale of 30 seconds which is prescribed per se and is associated with a further, expanding scale of seconds, it is possible to reduce the error to one third.

Through the fact that the expansion of the lower range is the same within each decadic time stage, it is possible to manage with only two time scales on the faceplate of the time relay, that is to say that provision is to be made, in the exemplified embodimentof the invention described below, for two time scales which extend for 0 to [0 and from 0 to 30 units of time respectively.

The use of fewer additional reduction gears does not increase the size of the per se known gearing, with the result that the time relays which have hitherto been mass-produced are not subjected to major modifications of any kind, and there are hardly any additional production costs.

The invention will now be described by way of example, with reference to the accompanying drawing, in which:

FIG. 1 is a diagrammatically simplified illustration of a time relay in accordance with the invention shown in perspective, and

- FIG. 2 is a graph, the abscissa of which shows the one component while the ordinate shows the error, in percentages, for various time ranges.

Referring to the drawings, FIG. 1 diagrammatically illustrates a time delay device on a faceplate l of which there are provided two annular indicating scales 2, 3

which are disposed coaxially with one another and which are either finished in different colors or, in a black/white design, each reflect the negative of the other. One scale extends over a time range of 0 to 30 units of time, whereas the other reproduces a time range of0 to ID units of time. Any desired delay period for the switching operation of, for example, a time delayed operating relay can be preselected on the scale by way of an adjusting knob 4, the said period being indicated in a visible manner by a pointer 5. An additional selector knob 6, which permits discontinuous time setting for different ranges, is disposed on a shaft with the adjusting knob 4 and is preferably located in the center of the latter and at its end face. In the exemplified embodiment, time ranges of 1 second, 10 seconds and seconds can be preselected for the relevant indicating scale 3, while time ranges of 3 and 30 seconds can be set for the indicating scale 2. The time range pertaining to the scale in question is reproduced, in the same color, on the corresponding segments of the selector knob 6, in order to ensure a particularly clear, confusion-free setting operation.

The time delay device for operation of a relay is actuated by way of a synchronous motor 7 which may, in known manner, either be continuous-running or start up at the same time as the electromagnet of a relay,

which is not illustrated here. The high output speed of the synchronous motor 7 is transmitted by the output pinion of the latter to gearing 8 so that it may be reduced by the latter in a suitable manner. While the reduction gears 8 are shown only schematically, each adjacent gear is intermated, and is constructed and selected of a reduced size corresponding with and precalculated to provide the time delayed or slower functioning of the time elapse wheel 11 in accordance with the dial settings. For this purpose, a double wheel arrangement 10 is disposed on the end of an adjusting shaft 9, which is fixedly connected to the selector knob 6, in such a way that the said arrangement can be selectively brought into engagement with said concentrically-located reduction gears.

The operation, which is effected by the switching magnet (not illustrated here), of coupling one gear of the double wheel arrangement to the time-elapse wheel 11, causes the latter to run until it has passed through the time range set over the indicating scale 2 or 3.

The coupling-in operation entails an error which is inherent in the time relay and is caused by the fact that the teeth of the double wheel arrangement 10 do not mesh immediately and in a slip-free manner with those of the time-elapse wheel 11 during the coupling operation. They may instead sometimes strike against one another at the moment of coupling, and only subsequently engage firmly with one another, after they have rotated by a certain fraction of the thickness of the gear tooth. This error resulting from the coupling operation is independent of the time set over the time scale 2 or 3. It therefore becomes noticeable in a particularly unfavorable manner in the case of time settings which lie in the lower range of a scale.

The reduction in the coupling error is now achieved, according to the invention, through the fact that, in the event of a small time range being set in the lower part of an indicating scale, in which case, therefore, the time-elapse wheel 11 would normally only pass through a small angle of rotation, use is made of the scale set above this time range in a suitable manner, in order to increase the return angle of the time-elapse wheel 11 to this extent. Thus, for example, in the case ofa setting of 1 second, which must have been carried out on the 3- second scale in a known time relay of this kind, it is now possible to use the l-second scale, as a result of which the time-elapse wheel does not merely pass through van angle of rotation of k of a full revolution, but instead performs an angular rotation extending over 300.

FIG. 2 shows the advantageous reduction in the time error, by a graphic illustration. The solid curves represent the time error in-dependence upon the time, in the case of a graduated time preselection of 3 or 30 units of time, while the broken curves and shaded areas represent a possible system of time stages. Since the time error based on the above-described coupling operation remains constant, from an absolute point of view, it makes itself felt particularly strongly when small time-elapse angles are selected. In this respect, the curves reproduced represent exponential functions in which the time error over the entire scale range amounts to i 0.5 percent as regards the thirty scale. 1f the time preselection were possible only over this one scale, the absolute error inherent in the time relay would amount, as can be seen from the graphic representation, to 1.5 percent at one unit of time, 3 percent at 0.5 unit of time, about 7.7 percent at 0.2 unit of time, etc.

According to the invention, the procedure is now no longer to select a setting such as is reproduced by the error curve which is completely filled in, but instead to select a setting such as is produced by the shaded areas. The preselection of time in the left-hand time interval in the graphic representation is accordingly carried out in such a way that use is made of the indicating scale 2,. which is filled in in black in FIG. 1, for the time range of l to 3 units of time, and of the indicating scale 3 for a time range of less than l second. The maximum error which can be obtained within the time interval of l to 3 units of time is, as can be seen from the raphic representation, 1.5 percent at the very most, w ereas,

in a time range of less than one unit of time and with a, still reasonable, time preselection of about 0.15 units, the said error amounts to only 3.5 percent compared with the IQ percent which would otherwise be the case.

According to the invention, therefore,.the time error can be reduced to one-third, which, as indicated in the foregoing description, also applies in the same way to the higher decadic time ranges.

As regards time setting in known time relays, the aim aspired to is linearity of the error in dependence upon the time preselection. This ideal state, however, requires substantially greater outlay and a completely different relay design and, in the last analysis, can only be achieved with a fully electronic relay. In this respect, the invention represents a proposal for approximating to this ideal state, while use is made of the previously known time relays without great additional expense.

I claim:

1. An electromechanical time delay device comprising a synchronous motor, a reduction gear system, a multi-wheel arrangement, a time elapse wheel adapted to'be selectively driven by the synchronous motor via the reduction gear system and multi-wheel arrangement, a time indicating scale and an adjuster knob associated therewith, the adjuster knob being connected with the time elapse wheel and operable to select a time delay period of actuation, a plurality of decadic ranges withineach of which the time delay period being continuously selectable, a second knob operatively associated with said multi-wheel arrangement for selecting a required one of said decadic ranges, each decadic range corresponding to a specific reduction ratio of the reduction gear system, and said multi-wheel arrangement with which each decadic range is associated useful for effecting expansion 'of the lower part of the selected decadic range.

2. A time relay according to claim 1, wherein the expansion of the lower ranges is identical within each decadic time stage, and the indicating'scale for the continuous preselection of the time delay is associated with only a single indicating scale which corresponds to constant spreading.

3. A time relay according to claim 1, wherein the indicating scales on the second selector knob are of multi-colored design, and are associated with the colors, corresponding the individual time ranges.

4. A time relay according to claim 1 wherein there are provided three decadic time ranges of one second, 10 seconds and seconds, which are associated with time ranges of 3 and 30 seconds.

5. The invention of claim 1 wherein said multi-wheel arrangement is pivotal to provide for its adjustment with respect to the reduction gear system for selection 

1. An electromechanical time delay device comprising a synchronous motor, a reduction gear system, a multi-wheel arrangement, a time elapse wheel adapted to be selectively driven by the synchronous motor via the reduction gear system and multiwheel arrangement, a time indicating scale and an adjuster knob associated therewith, the adjuster knob being connected with the time elapse wheel and operable to select a time delay period of actuation, a plurality of decadic ranges within each of which the time delay period being continuously selectable, a second knob operatively associated with said multi-wheel arrangement for selecting a required one of said decadic ranges, each decadic range corresponding to a specific reduction ratio of the reduction gear system, and said multi-wheel arrangement with which each decadic range is associated useful for effecting expansion of the lower part of the selected decadic range.
 1. An electromechanical time delay device comprising a synchronous motor, a reduction gear system, a multi-wheel arrangement, a time elapse wheel adapted to be selectively driven by the synchronous motor via the reduction gear system and multi-wheel arrangement, a time indicating scale and an adjuster knob associated therewith, the adjuster knob being connected with the time elapse wheel and operable to select a time delay period of actuation, a plurality of decadic ranges within each of which the time delay period being continuously selectable, a second knob operatively associated with said multi-wheel arrangement for selecting a required one of said decadic ranges, each decadic range corresponding to a specific reduction ratio of the reduction gear system, and said multi-wheel arrangement with which each decadic range is associated useful for effecting expansion of the lower part of the selected decadic range.
 2. A time relay accorDing to claim 1, wherein the expansion of the lower ranges is identical within each decadic time stage, and the indicating scale for the continuous preselection of the time delay is associated with only a single indicating scale which corresponds to constant spreading.
 3. A time relay according to claim 1, wherein the indicating scales on the second selector knob are of multi-colored design, and are associated with the colors, corresponding the individual time ranges.
 4. A time relay according to claim 1 wherein there are provided three decadic time ranges of one second, 10 seconds and 100 seconds, which are associated with time ranges of 3 and 30 seconds. 